Dean Hachamovitch, the General Manager over Internet Explorer at Microsoft c himes in on the future of the web:
The future of the web is HTML5. Microsoft is deeply engaged in the HTML5 process with the W3C. HTML5 will be very important in advancing rich, interactive web applications and site design. The HTML5 specification describes video support without specifying a particular video format. We think H.264 is an excellent format. In its HTML5 support, IE9 will support playback of H.264 video only.
H.264 is an industry standard, with broad and strong hardware support. Because of this standardization, you can easily take what you record on a typical consumer video camera, put it on the web, and have it play in a web browser on any operating system or device with H.264 support (e.g. a PC with Windows 7). Recently, we publicly showed IE9 playing H.264-encoded video from YouTube. You can read about the benefits of hardware acceleration here, or see an example of the benefits at the 26:35 mark here. For all these reasons, we’re focusing our HTML5 video support on H.264.
The elephant in the room with Hachamovitch is Silverlight, Microsoft’s media plugin. I’m not counting Microsoft as a true member of the HTML5 camp until IE supports it fully, along with a bunch of other open standards. I hope the IE team can walk the talk.